MimbleWimble(Tests): implement MW types

Add types needed for MimbleWimble transactions and implement
serialization.

Made all MimbleWimble types implement ISerializable and
interface and Read static method. Reuse NBitcoin's
BitcoinStream for serialization and deserialization, but don't
use its IBitcoinSerializable interface because it mixes reading
and writing in one method.

Added new test project for MimbleWimble tests. Added test for
peg-in transaction.

Added property-based tests for serialization and
deserilaization.

Added test that deserilizes transaction generated and
serialized by modified litecoin test (see [1]).

Added tests for parsing peg-out transaction and MW to MW
(HogEx) transaction.

[1] https://github.com/litecoin-project/litecoin/blob/5ac781487cc9589131437b23c69829f04002b97e/src/libmw/test/tests/models/tx/Test_Transaction.cpp

.gitignore

@@ -7,3 +7,5 @@
 /src/NLitecoin/bin
 /tests/NLitecoin.Tests/obj
 /tests/NLitecoin.Tests/bin
+/tests/NLitecoin.MimbleWimble.Tests/obj
+/tests/NLitecoin.MimbleWimble.Tests/bin

NLitecoin.sln

@@ -3,9 +3,11 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 17
 VisualStudioVersion = 17.6.33829.357
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "NLitecoin", "src\NLitecoin\NLitecoin.fsproj", "{1128287F-0435-4FA9-B4DD-420A9E1FDB23}"
+Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "NLitecoin", "src\NLitecoin\NLitecoin.fsproj", "{1128287F-0435-4FA9-B4DD-420A9E1FDB23}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NLitecoin.Tests", "tests\NLitecoin.Tests\NLitecoin.Tests.csproj", "{F954D3AC-36BC-483E-8DB1-4CC65DF1694D}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NLitecoin.Tests", "tests\NLitecoin.Tests\NLitecoin.Tests.csproj", "{F954D3AC-36BC-483E-8DB1-4CC65DF1694D}"
+EndProject
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "NLitecoin.MimbleWimble.Tests", "tests\NLitecoin.MimbleWimble.Tests\NLitecoin.MimbleWimble.Tests.fsproj", "{6A67D54D-BE2C-449F-88D2-D6739A5F3F89}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -21,6 +23,10 @@ Global
 		{F954D3AC-36BC-483E-8DB1-4CC65DF1694D}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{F954D3AC-36BC-483E-8DB1-4CC65DF1694D}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F954D3AC-36BC-483E-8DB1-4CC65DF1694D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6A67D54D-BE2C-449F-88D2-D6739A5F3F89}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6A67D54D-BE2C-449F-88D2-D6739A5F3F89}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6A67D54D-BE2C-449F-88D2-D6739A5F3F89}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6A67D54D-BE2C-449F-88D2-D6739A5F3F89}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/NLitecoin/Litecoin.fs

@@ -50,10 +50,14 @@ module private TxListExtensions =
 type LitecoinTransaction() = 
     inherit Transaction()
 
+    static let mwebExtensionTxFlag = 8uy
+
+    member val MimbleWimbleTransaction: Option<MimbleWimble.Transaction> = None with get, set
+
     override self.GetConsensusFactory() = LitecoinConsensusFactory.Instance
 
     member private self.Read (stream: BitcoinStream) (witSupported: bool) =
-        let flags = 0uy
+        let mutable flags = 0uy
         self.nVersion <- stream.ReadWrite self.nVersion
         // Try to read the vin. In case the dummy is there, this will be read as an empty vector.
         stream.ReadWrite(&self.vin)
@@ -64,7 +68,7 @@ type LitecoinTransaction() =
 
         if self.vin.Count = 0 && witSupported && not hasNoDummy then
             // We read a dummy or an empty vin.
-            let flags = stream.ReadWrite flags
+            flags <- stream.ReadWrite flags
             if flags <> 0uy then
                 // Assume we read a dummy and a flag.
                 stream.ReadWrite(&self.vin)
@@ -79,22 +83,17 @@ type LitecoinTransaction() =
             stream.ReadWrite(&self.vout)
             self.vout <- self.vout.WithTransaction self
 
-        let flags =
-            if ((flags &&& 1uy) <> 0uy) && witSupported then
-                // The witness flag is present, and we support witnesses.
-                let wit = Witness self.Inputs
-                wit.ReadWrite stream
-                flags ^^^ 1uy
-            else
-                flags
-        let flags =
-            if (flags &&& 8uy) <> 0uy then //MWEB extension tx flag
-                (* The MWEB flag is present, but currently no MWEB data is supported. 
-                    * This fix just prevent from throwing exception bellow so cannonical litecoin transaction can be read
-                    *)
-                flags ^^^ 8uy
-            else
-                flags
+        if ((flags &&& 1uy) <> 0uy) && witSupported then
+            // The witness flag is present, and we support witnesses.
+            let wit = Witness self.Inputs
+            wit.ReadWrite stream
+            flags <- flags ^^^ 1uy
+
+        if (flags &&& mwebExtensionTxFlag) <> 0uy then
+            let version = ref 0uy
+            stream.ReadWrite version
+            self.MimbleWimbleTransaction <- Some(MimbleWimble.Transaction.Read stream)
+            flags <- flags ^^^ 8uy
 
         if flags <> 0uy then
             // Unknown flag in the serialization
@@ -118,6 +117,12 @@ type LitecoinTransaction() =
             else
                 0uy
 
+        let flags = 
+            if self.MimbleWimbleTransaction.IsSome then 
+                flags ||| mwebExtensionTxFlag 
+            else 
+                flags 
+
         let flags = 
             if flags <> 0uy then
                 // Use extended format in case witnesses are to be serialized.
@@ -135,6 +140,12 @@ type LitecoinTransaction() =
             let wit = Witness self.Inputs
             wit.ReadWrite stream
 
+        match self.MimbleWimbleTransaction with
+        | Some mwebTransaction -> 
+            stream.ReadWrite MimbleWimble.Transaction.Version |> ignore
+            (mwebTransaction :> MimbleWimble.ISerializeable).Write stream
+        | None -> ()
+
     override self.ReadWrite(stream: BitcoinStream) =
         let witSupported = 
             (((uint32 stream.TransactionOptions) &&& (uint32 TransactionOptions.Witness)) <> 0u) &&